Collapsible feed mechanism

ABSTRACT

A collapsible feed mechanism for providing radial support to a longitudinally extending member and for preventing bending and buckling of said longitudinally extending member during the axial advancement thereof while under an axial compressive load, such collapsible feed mechanism for residing axially displaceably within an outer support structure, including a plurality of axially displaceable radial support members positioned around the longitudinally extending member; each radial support member having an outer axial surface and an inner axial surface; the outer axial surfaces of alternate ones of the radial support members being greater in axial length than the inner axial surfaces of the alternate ones of the radial support members; the inner axial surfaces of other alternate ones of the radial support members being greater in axial length than the outer axial surfaces of the other alternate ones of the radial support members; the outer axial surfaces of greater axial length for slidably engaging the outer support structure during the axial displacement of the radial support members and for preventing the tendency of the axially displaceable support members to rotate with respect to an axis perpendicular to the longitudinally extending member and bind during the axial displacement of the radial support members; the inner axial surfaces for slidably engaging the longitudinally extending member during the axial displacement of the radial support members and for providing the radial support to the longitudinally extending member.

United States Patent [191 La Lena et al.

[ COLLAPSIBLE FEED MECHANISM [75] inventors: George A. La Lena, Warminster;

Jack D. Stewart, Doylestown, both 1 of Pa. r

[73] Assignee: Princeton Metal Systems Corporation, Montgomery Township, NJ.

[22] Filed: Dec. 29, 1972 [21] Appl. No.: 319,284

Primary Examiner-Richard J. Herbst Attorney, Agent, or Firm-Popper, Bain, Bobis, Gilfillan & Rhodes [5 7] ABSTRACT A collapsible feed mechanism for providing radial support to a longitudinally extending member and for pre- [4 1 Feb. 12, 1974 venting bending and buckling of said longitudinally extending member during the axial advancement thereof while under an axial compressive load, such collapsible feed mechanism for residing axially displaceably within an outer support structure, including a plurality of axially displaceable radial support members positioned around the longitudinally extending member; each radial support member having an outer axial surface and an inner axial surface; the outer axial surfaces of alternate ones of the radial support members being greater in axial length than the inner axial surfaces of the alternate ones of the radial support members; the inner axial surfaces of other alternate ones of the radial support members being greater in axial length than the outer axial surfaces of the other alternate ones of the radial support members; the outer axial surfaces of greater axial length for slidably engaging the outer support structure during the axial displacement of the radial support members and for preventing the tendency of the axially displaceable support members to rotate with respect to an axis perpendicular to'the longitudinally extending member and bind during the axial displacement of the radial support members; the inner axial surfaces for slidably engaging the longitudinally extending member during the axial displacement of the radial support members and for providing the radial support to the longitudinally extending member.

8 Claims, 7 Drawing Figures SHEET 2 OF 2 PATENTEDFEB12 m4 FIG.5 FIG. 6

1 COLLAPSIELE FEED MECHANISM BACKGROUND OF THE INVENTION structures during such advancement.

It is known to those skilled in the art that longitudinally extending members such as long, slender rods having a length to least radius of gyration ratio in excess of 80:1, are commonly referred to as slender columns and are particularly susceptible to bending and buckling when subjected to large, axially directed,

. compressive loads.

The susceptibility of rods in general and slender columns in particular to bending and buckling not only limits the capability of the rod or column to support axially directed compressive loads, but also causes misalignment and bending difficulties when it is necessary to pass a rod or slender column axially through one or more aligned orifices. For example, the extrusion of wire from a billet being subjected to high hydrostatic pressure in a fluid, tight pressure vessel wherein the ex trusion is accomplished by advancing a ram-mounted die upwardly of the billet into a bore in the vessel, ordinarily requires the use of a hollow die ram which is a rod, or rod-like member,-falling within the definition of a slender column. The forces of extrusion are quite high, thus increasing the likelihood of bending or buckling. Further, the alignment of the die ram with the pressure vessel bore is very important in order to preclude binding which might interfere with advancement of the die at a constant or controlled rate. In this typical situation, therefore, great care must be taken to support the die ram radially during the axial advancement against any unacceptable'bending or buckling, and to maintain the die ram in co-axial alignment with the pressure vessel.

A collapsible feed mechanism for supporting slender columns in compression wherein the application is hydrostatic extrusion of billets is described in full in US Pat. No. 3,548,625 to F. J. Fuchs, Jr. The slenderness ratio is minimized by a series of sliding die stem support spacers, or aligning plates, connected such that their maximum separation is limited to satisfy the slenderness ratio requirement of the slender column in the open position and the'surfaces of each spacer will be in contact during the closed position. As is known in the art, it is desirableto limit the spacers thicknesses to the smallest value possible primarily because the spacer thickness utilizes volume which in turn adds to the requirement for increased die stem or slender column length. If the spacers are ,too thin, there is a tendency for them to translate, or rotate, about an axis parallel to the vertical surface of the spacer and perpendicular to its center line or the centerline ofthe slender column. To avoid this tendency toward translation or rotation, it is a general rule of thumb that the axial spacer length or thickness should be approximately equal to its diameter. However, for those knowledgeable in the art, adaptation of this design parameter is highly undesirknown to the collapsible able, and in certain instances virtually intolerable, in that it unwantedly extends the length of the extrusion machine, the slender column of die stem (with the resulting adverse effect on alignment) equivalent to the sum of the thicknesses of the die stem spacers. An expedient known to the prior art for overcoming the resultant binding of the OD of the spacers against their retainer wall as well as the ID of the spacers against the die stem due to such rotational problem, is to fabricate curved surfaces onto the OD and ID of the spacers. Thus, any tendency to rotate will not create a binding or otherwise interfering condition. However, such expedient has not proven to be altogether satisfactory as such rounded surfaces can cause too much rotation and hence can result in lack of full radial'support to the die ram.

SUMMARY In accordance with the present invention the abovenoted prior art problems are overcome by providing a collapsible feed mechanism for providing radial support to 'a longitudinally extending member, which mechanism includes aligning members or radial support members structured in such a manner that alternate ones have outer axial surfaces of sufficient length, and that other alternate ones have inner axial surfaces of sufiicient length to avoid or preclude the tendency to rotate or translate and bind, and at the same time are structured in such a manner that they will nestle or collapse in such a manner that in the fully collapsed or nestled position they will occupy a minimum volume or axial length or at least a volume no greater than that feed mechanisms of the prior art.

' DESCRIPTION OF THE DRAWINGS FIGS. 1, 2 and 3 are diagrammatic presentations of a collapsible feed mechanism of the present invention showing various conditions of expansion and contraction; and

FIGS. 4, 5 and 6 are enlarged schematic views showing detailed structural configuration of the radial support members of the collapsible feed mechanism of the present invention.

DESCRIPTION OF THE INVENTION Referring to FIGS. ll'3, there is shown a collapsible feed mechanism embodying the present invention and indicated by general numerical designation 10. In the diagrammatic presentation of the present invention, the collapsible feed mechanism 10 is for providing radial support to a longitudinally extending member, such as die ram 12, during the axial advancement of the die ram while under an axial compressive load. The collapsible feed mechanism 10 resides axially, displaceably within a suitable outer support structure identified by general numerical designation 14.

More particularly, the collapsible feed mechanism 10 is for providing radial support to the die ram 12 during its axial advancement into a pressure vessel 16 to hydrostatically extrude a metal billet 18 into, for example, wire 20in the manner known to those skilled in the hydrostatic extrusion art. Further, the collapsible feed mechanism 10 is also for maintaining the die ram 12 in co-axial alignment with the bore 22 of the pressure vessel 16 during the axial advancement of the die ram into the bore 16. More particularly with regard to the hydrostatic extrusion of the billet 18, the die ram 12 is suitably secured to a drive plate 24 to which are suitably connected a plurality of drive rods 26. Each drive rod is suitably connected to a piston (not shown) mounted for reciprocable-movement in a power cylinder 28. Upon the advancement of the drive rods to the left, the drive rods in turn transmit leftward movement to the drive plate 24 which in turn axially displaces the die ram 12 into the pressure vessel 14 to extrude the billet 18, and in doing so, places the die ram 12 under a heavy axial compressive load.

Referring still to FIGS. I3, and referring more particularly to the structure of the collapsible feed mechanism of the present invention, the collapsible feed mechanism includes a plurality of axially displaceable, generally annular, radial support members 32, 34, 36 and 38 which reside axially displaceably in the outer support structure 14.

It will be noted that alternate radial support members 32 and 36 are provided with outer axial surface 42 greater in axial length than their inner axial surfaces 43, and that alternate radial support members 34 and 38 are provided with inner axial surfaces 44 greater in axial length than their outer axial surfaces 45.

Further, it will be noted that the radial support members are provided with outer radial portions, defining the respective outer axial surfaces, which are complementary in configuration such that when the radial support members engage, as shown in FIG. 7, they have a combined axial length 51 which is less than the combined axial length of the radial members were all of such members to have the configuration of radial members 32 and 36.

Upon axial displacement of the radial support members 32, 34, 36 and 38, the inner axial surfaces 43 and 44 slidably engage and provide radial support to the axially advanced or displaced die stem 12 and, the inner axial surfaces 44 of greater axial length prevent the tendency of the radial support members to rotate with respect to an axis perpendicular to the die ram 12 and bind. The outer axial surfaces 42 and 45,'of greater axial length, upon such axial displacement of the radial support members, slidably engage the inner surface of the outer support structure 14, and, the outer axial surfaces 42 of greater axial length avoid or preclude any tendency of the radial support members to rotate or translate with respect to an axis perpendicular to the die ram 12 thereby preventing or precluding any binding of the radial support members during their axial advancement to provide radial support to the advancing die ram 12.

As noted above, another primary consideration with collapsible feed mechanisms is that they are able to be collapsed in a minimum volume, or minimum axial length, so as to permit, for example, the die ram 12, and associated extrusion structure, to be of minimum axial length because, as may be best seen in FIG. 3, the die ram 12 for complete advancement into the pressure vessel 16 must be of an axial length which includes the collapsed axial length of the collapsible feed mechanism 10. Accordingly, the collapsible feed mechanism 10 of the present invention, in addition to precluding the tendency of the radial support members 10 to rotate or translate about the die ram 12, is also structured so as to permit the radial support members 32, 34, 36 and 38 to be collapsed or nestled into a minimum axial length.

Accordingly, and referring now to FIGS. 5-7, it will be noted that alternate ones of the radial support members, e.g. radial support members 32 and 36, are provided with one configuration, and that other alternate ones of the radial support members, e.g. radial support members 34 and 38, are provided with another configuration; such configurations being complementary as shown thereby permitting the radial support members to engage as shown in FIG. 7.

Further, it will be understood by those skilled in the collapsible feed mechanism art, that, as in the collapsible feed mechanism in the aforementioned patent to F. J. Fuchs, .Ir., the radial support members 32, 34, 36 and 38 of the present invention are provided with means for axially positioning the radial support members at predetermined points along the die ram 12 upon the retraction or expansion of the collapsible feed mechanism, namely, and as is also known to those skilled in the art, the collapsible feed mechanism 10 of the present invention is provided with lost motion mechanism including a plurality of headed bolts 52 (FIGS. 1, 2 and 3) and apertures 54 and (FIG. 4) in which the bolts 52 slidably reside and extend therethrough; further, it will be understood that only certain of the bolts 52 of the plurality are shown in FIGS. 1-3 for purposes of simplifying the drawings and clarity of presentation. More specifically, as shown in FIGS. 1-3, bolts 52 interconnect radial support members 36 and 38, the bolts 52 being threadedly secured in radial support member 36 and extending slidably and loosely through apertures 60 formed in radial support member 38 with the heads of the bolts 56 residing on the opposite side of radial support member 38. Apertures 60 are larger in diameter than the bolts 52 thereby permitting the free passage of the bolts therethrough, but are smaller in diameter than the diameter of the bolt heads 56 thereby preventing passage of the bolt heads therethrough. Similarly, it will be understood that although not shown, radial support members 32 and 34 and 34 and 36, and drive plate 24 and radial support member 38 are provided with bolts 52 and apertures 60. Further, and with particular regard to the apertures, the structural details of a representative radial support member, e.g. radial support member 38, are shown in FIG. 4. The radial support member 38 is provided with the plurality of smaller apertures 60, mentioned above, for permitting free passage therethrough of the bolts 52 and for preventing passage therethrough of the bolt heads 56, and is further provided with a plurality of apertures 54 for permitting the free passage therethrough of the bolts and bolt heads, and in particular the bolt heads of the bolts 52 interconnecting radial support members 32 and 34 and 34 and 36 upon the collapse of the feed mechanism as shown in FIG. 3. Also, radial support member 38 is provided with a plurality of apertures 62 for permitting the free passage therethrough of the drive rods 26. Further, radial support member 38 is provided with a centrally formed aperture 66 for closely, but slidably, permitting the passage therethrough of die ram 12; it being understood, of course, that aperture 36 is defined by the inner axial surface 44 of the radial support member.

Similarly, it will be understood that radial support members 32, 34, 36 and drive plate 24 are provided with smaller apertures 60, larger apertures 54, apertures 62 and aperture 60, but that drive plate 32 is only provided with apertures 62 and 66.

OPERATION With regard to the operation of the collapsible feed mechanism of the present invention, it will be assumed that the structural members occupy the position shown in FIG. 1 and that it is desired to extrude the billet 18 into wire 20.

The power cylinders 28 will be actuated by suitable means, not shown, to impart leftward movement to the drive rods 26, which, in turn, impart leftward movement to the drive plate 24 which, in turn, advances the die ram 12 leftwardly into the pressure vessel 16, filled with a hydrostatic fluid medium 17 to hydrostatically extrude the metal billet 18 into wire 20; it being understood that such leftward movement or axial advancement of the die ram 12 into the vessel 16 places the die ram under a large axial compressive load. During the leftward movement of the drive plate 24 from the position shown in FIG. 1 to the position shown in FIG. 2,

no movement will be imparted to the radial support members 32, 34, 36 and 38, the headed bolts interconnecting radial support member 38 and the drive plate 24 passing freely through the apertures formed in the drive plate and in which the headed bolts reside. Upon the drive plate 24 reaching the position shown in FIG. 2, the drive plate engages radial support member 38 and axially displaces the radial support member leftwardly as viewed in FIG. 2. The radial support member v38, under the influence of leftwardly moving drive plate 24, is displaced leftwardly until it engages radial support member 36 which radial support member 36 is in turn advanced or displaced axially leftwardly until it engages radial support member 34 to axially displace radial support member 34 leftwardly until it engages radial support member 32 which in turn is displaced leftwardly until it engages the annular stop member 73 shown in FIG. 3. During the leftward axial displacement of the radial support member 38'until it engages radial support member 36, it will be understood that the headed bolts 52 interconnecting radial support member 36 with radial support member 38 pass freely through the apertures 60 formed in radial support member 38 and that such bolts and their heads pass through apertures54 formed in the drive plate 24. Similarly, it will be understood that duringthe leftward axial displacement of the drive plate 24, radial support member 38 and radial support member 36 leftwardly into engagement with radial support member 34, that the headed bolts interconnecting radial support member 34 with radial support member 36 pass freely through the apertures 60 formed in radial support member 36 and that such bolts and their heads pass freely through larger apertures 54 formed in radial sup port members 36 and 38 and drive plate 24; similarly with respect to radial support members 32 and 34.

Upon the completion of the extrusion of the billet 18 into wire 20, the power cylinders are operated to move the drive rods 26 rightwardly to return the die ram 12 and drive plate 24 to their initial positions shown in FIG. 1. During the return of the die ram 12 and drive plate 24, the lost motion linkage positions the radial support members at the spaced points along the die ram 12 as shown in FIG. 1. More particularly, upon the initial rightward movement of the drive plate 24, only the drive plate 24 is moved rightwardly with the radial support members 32, 34, 36 and 38 remaining in their leftward position shown in FIG. 3. The drive plate 24 moves rightwardly until it engages the heads 56 of the bolts 52 interconnecting the drive plate and radial support member 38 whereupon rightward movement or axial displacement is imparted to the radial support member 38. The radial support members 32, 34 and 36 remain in their leftward position shown in FIG. 3 until the radial support member 38 engages the heads 56 of the bolts 52 interconnecting radial support members 36 and 38 whereupon rightward movement or axial displacement is imparted to the radial support member 36; similarly, with regard to radial support members 32 and 34. Upon the drive rods 26 having restored the drive plate 24 to its initial position shown in FIG. 1, the lost motion linkage including the bolts 52 and apertures 54 and 60 will have positioned the radial support members 32, 34, 36 and 38 at their initial axial positions along the die ram 12 as shown in FIG. 1.

It will be understood by those skilled in the art that the lost motion linkage instead of employing bolts threaded into the radial support members could employ bolts having heads on each end and residing slidably in smaller apertures 60 formed in the radial support members interconnected by the bolts.

It will be further understood by those skilled in the art that many modifications and variations may be made in the collapsible feed mechanism of the present invention without departing from the spirit and scope thereof.

What is claimed is:

1. Collapsible feed mechanism for providing radial support to a longitudinally extending member having a longitudinal axis and for preventing bending and buckling of said longitudinally extending member during the axial advancement thereof while under an axial compressive load, and said collapsible feed mechanism for residing axially displaceably within an outer support structure, comprising:

a plurality of axially displaceable radial support members positioned around said longitudinally extending member;

each radial support member having an outer axial surface and an inner axial surface;

said outer axial surfaces of alternate ones of said radial support members being greater in axial lengththan said inner axial surfaces of said alternate ones of said radial support members;

said inner axial surfaces of other alternate ones of said radial support members being greater in axial length than said outer axial surfaces of said other alternate ones of said radial support members;

said outer axial surfaces for slidably engaging said outer support structure during the axial displacement of said radial support members and said inner axial surfaces for slidably engaging said longitudinally extending member during the axial displacement of said radial support members to provide said radial support to said longitudinally extending member;

said outer axial surfaces of greater axial length and said inner axial surfaces of greater axial length for preventing any tendency" of said axially displaceable support members to be displaced from a substantially normal plane with respect to said longitudinal axis of said longitudinally extending member and bind during said axial displacement of said radial support members.

2. Collapsible feed mechanism according to claim 1, wherein said radial support members are provided with a generally annular configuration.

3. Collapsible feed mechanism according to claim 1 further including means for axially positioning said radial support members at spaced points along said longitudinally extending member upon the expansion of said collapsible feed mechanism.

4. Collapsible feed mechanism according to claim 3 wherein said axially positioning means comprises lost motion linkage.

5. Collapsible feed mechanism for providing radial support to a longitudinally extending member and for preventing bending and buckling of said longitudinally extending member during the axial displacement thereof while under an axial compressive load, and said collapsible feed mechanism for residing axially displaceably within an outer support structure, comprismg:

a plurality of generally annular axially displaceable radial support members positioned around said longitudinally extending member;

each of said radial support members provided with an inner axial surface and an outer axial surface;

said outer axial surfaces of alternate ones of said radial support members being greater in axial length than said inner axial surfaces of said alternate ones of said radial support members;

said inner axial surfaces of other alternate ones of said radial support members being greater in axial length than said outer axial surfaces of said other alternate ones of said radial support members;

said outer axial surfaces of greater axial length for slidably engaging said outer support structure during the axial displacement of said radial support members and for preventing the tendency of said alternate ones of said axially displaceable radial support members to rotate with respect to an axis perpendicular to said longitudinally extending member and bind during the axial displacement of said alternate ones of said radial support members;

said inner axial surfaces of greater axial length for slidably engaging said longitudinally extending member during the axial displacement of said radial support members and for preventing the tendency of said other alternate ones of said axially displaceable radial support members to rotate with respect to said axis perpendicular to said longitudinally extending member and bind during the axial displacement of said other alternate ones of said radial support members; and

said outer axial surfaces for slidably engaging said outer support structure during said axial displacement of said radial support members and said inner axial surfaces for slidably engaging said longitudinally extending member during said axial displacement of said longitudinally extending member and during said axial displacement of said radial support member whereby said radial support members provide said radial support to said longitudinally extending member.

6. Collapsible feed mechanism according to claim 5 further including means for axially positioning said radial support members at spaced points along said longitudinally extending member upon the expansion of said collapsible feed mechanism.

7. Collapsible feed mechanism according to claim 6 wherein said axially positioning means comprises lost motion linkage.

8. Collapsible feed mechanism according to claim 5 wherein said radial support members are provided with outer radial portions of a predetermined complementary configuration such that the radial support members can engage axially in a combined axial length less than they could were all of the radial support members provided with the same outer radial configuration. 

1. Collapsible feed mechanism for providing radial support to a longitudinally extending member having a longitudinal axis and for preventing bending and buckling of said longitudinally extending member during the axial advancement thereof while under an axial compressive load, and said collapsible feed mechanism for residing axially displaceably within an outer support structure, comprising: a plurality of axially displaceable radial support members positioned around said longitudinally extending member; each radial support member having an outer axial surface and an inner axial surface; said outer axial surfaces of alternate ones of said radial support members being greater in axial length than said inner axial surfaces of said alternate ones of said radial support members; said inner axial surfaces of other alternate ones of said radial support members being greater in axial length than said outer axial surfaces of said other alternate ones of said radial support members; said outer axial surfaces for slidably engaging said outer support structure during the axial displacement of said radial support members and said inner axial surfaces for slidably engaging said longitudinally extending member during the axial displacement of said radial support members to provide said radial support to said longitudinally extending member; said outer axial surfaces of greater axial length and said inner axial surfaces of greater axial length for preventing any tendency of said axially displaceable support members to be displaced from a substantially normal plane with respect to said longitudinal axis of said longitudinally extending member and bind during said axial displacement of said radial support members.
 2. Collapsible feed mechanism according to claim 1, wherein said radial support members are provided with a generally annular configuration.
 3. Collapsible feed mechanism according to claim 1 further including means for axially positioning said radial support members at spaced points along said longitudinally extending member upon the expansion of said collapsible feed mechanism.
 4. Collapsible feed mechanism according to claim 3 wherein said axially positioning means comprises lost motion linkage.
 5. Collapsible feed mechanism for providing radial support to a longitudinally extending member and for preventing bending and buckling of said longitudinally extending member during the axial displacement thereof while under an axial compressive load, and said collapsible feed mechanism for residing axially displaceably within an outer support structure, comprising: a plurality of generally annular axially displaceable radial support members positioned around said longitudinally extending member; each of said radial support members provided with an inner axial surface and an outer axial surface; said outer axial surfaces of alternate ones of said radial support members being greater in axial length than said inner axial surfaces of said alternate ones of said radial support members; said inner axial surfaces of other alternate ones of said radial support members being greater in axial length than said outer axial surfaces of said other alternate ones of said radial support members; said outer axial surfaces of greater axial length for slidably engaging said outer support structure during the axial displacement of sAid radial support members and for preventing the tendency of said alternate ones of said axially displaceable radial support members to rotate with respect to an axis perpendicular to said longitudinally extending member and bind during the axial displacement of said alternate ones of said radial support members; said inner axial surfaces of greater axial length for slidably engaging said longitudinally extending member during the axial displacement of said radial support members and for preventing the tendency of said other alternate ones of said axially displaceable radial support members to rotate with respect to said axis perpendicular to said longitudinally extending member and bind during the axial displacement of said other alternate ones of said radial support members; and said outer axial surfaces for slidably engaging said outer support structure during said axial displacement of said radial support members and said inner axial surfaces for slidably engaging said longitudinally extending member during said axial displacement of said longitudinally extending member and during said axial displacement of said radial support member whereby said radial support members provide said radial support to said longitudinally extending member.
 6. Collapsible feed mechanism according to claim 5 further including means for axially positioning said radial support members at spaced points along said longitudinally extending member upon the expansion of said collapsible feed mechanism.
 7. Collapsible feed mechanism according to claim 6 wherein said axially positioning means comprises lost motion linkage.
 8. Collapsible feed mechanism according to claim 5 wherein said radial support members are provided with outer radial portions of a predetermined complementary configuration such that the radial support members can engage axially in a combined axial length less than they could were all of the radial support members provided with the same outer radial configuration. 